...
display_series( \%series );
...
display_series( \%series );
...

sub display_series
{
    my( $series ) = @_;
    
    if ($series->{depth} >= MIN_DEPTH)
    {
        print join(',', $series->{name}, $series->{start}, $series->{end},
                        $series->{end} - $series->{start} + 1), "\n";
    }
}